Overlay-tolerant via mask and reactive ion etch (RIE) technique

ABSTRACT

A method is provided that includes first etching a substrate according to a first mask. The first etching forms a first etch feature in the substrate to a first depth. The first etching also forms a sliver opening in the substrate. The sliver opening may then be filled with a fill material. A second mask may be formed by removing a portion of the first mask. The substrate exposed by the second mask may be etched with a second etch, in which the second etching is selective to the fill material. The second etching extends the first etch feature to a second depth that is greater than the first depth, and the second etch forms a second etch feature. The first etch feature and the second etch feature may then be filled with a conductive metal.

BACKGROUND

The present disclosure relates generally to semiconductor integratedcircuits (ICs). More particularly, the present disclosure relates tomethods and structures including lines and vias as used in integratedcircuits (ICs).

In order to be able to make integrated circuits (ICs), such as memory,logic, and other devices, of higher integration density than currentlyfeasible, one has to find ways to further downscale the dimensions offield effect transistors (FETs), such as MOSFETs, and complementarymetal oxide semiconductors (CMOS), and of similarly-scaled conductivewiring between them. Scaling achieves compactness and improves operatingperformance in devices by shrinking the overall dimensions and operatingvoltages of the device while maintaining the device's electricalproperties.

Increased scaling can provide some difficulties with forming small-pitchmetal wiring and the necessary interlevel vias. Typically, self alignedprocesses are employed for forming the wiring and vias to the device, inwhich metal troughs for the lines are defined in an interleveldielectric mask or in a hard mask, and the vias are printed and etchedin such a way that only the union of the metal trough and the via shapeform vias down to the underlying metal layer. Reliable printing of viascan be problematic for aggressively scaled devices, so vias having a barshape may be employed to increase pattern printability. Typically, a viaopening is formed where the via bar shape crosses the union with themetal trough for the metal line. However, if the bar overlaps onto anadjacent metal trough than the union can result in an undesirable viathat could short the lines formed in the metal trough that areinterconnected by the undesirable via.

SUMMARY

In one embodiment, a method is provided that includes first etching asubstrate according to a first mask. The first etching forms a firstetch feature in the substrate to a first depth. The first etching alsoforms a sliver opening in the substrate. The sliver opening may then befilled with a fill material. A second mask may be formed by removing aportion of the first mask. The substrate exposed by the second mask maybe etched with a second etch, in which the second etching is selectiveto the fill material. The second etching extends the first etch featureto a second depth that is greater than the first depth, and the secondetch forms a second etch feature. The first etch feature and the secondetch feature may then be filled with a conductive metal.

In another embodiment, a method is provided that includes forming afirst mask layer on a substrate that is patterned to correspond tolines, and forming a second mask layer on the substrate over the firstmask layer. The combination of the first mask layer and the second masklayer provides a pattern that corresponds to vias. A shared openingregion is also present between openings in the first mask layer and thesecond mask layer. The shared opening region may be filled with aconformal fill layer. The substrate may be first etched using the firstmask layer and the second mask layer, in which the first etch forms afirst opening to a first depth into the substrate. The second mask layermay be removed. The substrate may then be etched with a second etchusing the first mask layer. The second etch may be selective to thefirst mask layer, wherein the first opening is extended to a seconddepth to provide openings for the vias. Openings for the lines areprovided by at least one second opening that is also etched into thesubstrate by the second etching. At least one of the openings for thevias and the openings for the lines is then filled with a conductivematerial.

In another aspect, a structure is provided that includes an array ofconductive pathways. The structure may include a substrate that iscomposed of a dielectric material. An array of lines having a lengththat extends along a horizontal direction of the substrate is present.At least one of the lines has a dimple region or a pinch region on itssidewall at a lower surface of the line. An array of vias having avertical dimension that is perpendicular to the length of each of thelines in the array of conductive lines is also present. At least one ofthe vias in the array intersects with at least one of the lines.

In another embodiment, a structure including an array of conductivepathways is provided that includes a substrate comprised of a dielectricmaterial, and an array of lines having a length that extends along ahorizontal direction of the substrate. A sliver material may extendalong a sidewall of at least one line of the array of conductive lines.An array of vias may also be present, in which each via of the an arrayof vias has a vertical dimension that is perpendicular to the length ofthe lines, wherein at least one via in the array of vias is in contactwith at least one line of the array of lines.

DESCRIPTION OF THE DRAWINGS

The following detailed description, given by way of example and notintended to limit the present disclosure solely thereto, will best beappreciated in conjunction with the accompanying drawings, wherein likereference numerals denote like elements and parts, in which:

FIG. 1 is a side cross-sectional view of forming a first mask layer on asubstrate that is patterned to correspond to lines on the substrate, andforming a second mask layer that is patterned to correspond to vias onthe substrate, in accordance with one embodiment of the presentdisclosure.

FIG. 2 is a side cross-sectional view depicting one embodiment of firstetching the substrate using the first mask layer and the second masklayer as a first etch mask, wherein the etching forms a first opening toa first depth into the substrate and a shared opening region between thefirst mask layer and the second mask layer forms a sliver opening in thesubstrate, in accordance with the present disclosure.

FIG. 3 is a side cross-sectional view depicting removing the second masklayer, in accordance with one embodiment of the present disclosure.

FIG. 4 is a side cross-sectional view depicting one embodiment ofconformally depositing a fill material layer to fill the sliver opening,wherein a first portion of the fill material layer that is deposited onthe first opening has a first thickness, and a second portion of thefill material layer that is present in the sliver opening has a secondthickness that fills the sliver opening, in accordance with the presentdisclosure.

FIG. 5 is a side cross-sectional view depicting one embodiment ofisotropically etching the fill material layer to remove the firstportion of the fill material layer, in which the second portion of thefill material layer remains in the sliver opening, in accordance withthe present disclosure.

FIG. 6 is a side cross-sectional view depicting one embodiment of secondetching the substrate using the first mask layer as a second etch maskwith an etch that is selective to the first mask layer and the fillmaterial that fills the sliver opening, in accordance with the presentdisclosure.

FIG. 7 is a side cross-sectional view depicting removing the fillmaterial that fills the sliver opening, in accordance with oneembodiment of the present disclosure.

FIG. 8 is a side cross-sectional view depicting another embodiment ofremoving the fill material that fills the sliver opening, in accordancewith the present disclosure.

FIG. 9 is a side cross-sectional view depicting the lines and viasformed using another embodiment of the present disclosure, in which thestructure is formed by conformally depositing the fill material thatfills the sliver opening over the entire structure depicted in FIG. 3followed by etching the blanket fill material using the second etch thatis depicted in FIG. 6, in accordance with the present disclosure.

FIG. 10A is a side cross-sectional view depicting filling at least oneof the openings for the vias and the openings for the lines with aconductive material, wherein the at least one of the vias contacts anunderlying line, in accordance with one embodiment of the presentdisclosure.

FIG. 10B is a top down planar view along section line B-B in FIG. 10A.

FIG. 10C is a side cross-sectional view depicting filling at least oneof the openings for the vias and the openings for the lines with aconductive material, wherein the at least one of the vias contacts anunderlying semiconductor device, in accordance with one embodiment ofthe present disclosure.

FIG. 10D is a side cross-sectional view depicting a pinch region presentat a intersection between the base and sidewall of a line, in accordancewith one embodiment of the present disclosure.

FIG. 10E is a side cross-sectional view depicting a sliver dielectricpresent along a sidewall of a line, in accordance with one embodiment ofthe present disclosure.

FIG. 11 is a side cross-sectional view depicting one embodiment ofdepositing a conformal fill layer on the structure depicted in FIG. 1,wherein a first portion of the conformal fill layer that is deposited inthe shared opening region has a first thickness, and a remaining portionof the conformal fill layer that is present on the first mask, secondmask and the substrate has a second thickness, in accordance with thepresent disclosure.

FIG. 12 is a side cross-sectional view depicting isotropically etchingthe conformal fill layer depicted in FIG. 11 to remove the remainingportion of the conformal fill layer that is not present in themisalignment opening, wherein the first portion of the conformal filllayer remains in the shared opening region, in accordance with oneembodiment of the present disclosure.

FIG. 13 is a side cross-sectional view depicting first etching thesubstrate depicted in FIG. 12 using the first mask layer and the secondmask layer as a first etch mask, wherein the etching forms a firstopening to a first depth into the substrate, in accordance with oneembodiment of the present disclosure.

FIG. 14 is a side cross-sectional view depicting second etching thesubstrate that is depicted in FIG. 13 using the first mask layer as asecond etch mask with an etch that is selective to the first mask layer,in accordance with one embodiment of the present disclosure.

DETAILED DESCRIPTION

Detailed embodiments of the claimed structures and methods are disclosedherein; however, it is to be understood that the disclosed embodimentsare merely illustrative of the claimed structures and methods that maybe embodied in various forms. In addition, each of the examples given inconnection with the various embodiments are intended to be illustrative,and not restrictive. Further, the figures are not necessarily to scale,some features may be exaggerated to show details of particularcomponents. Therefore, specific structural and functional detailsdisclosed herein are not to be interpreted as limiting, but merely as arepresentative basis for teaching one skilled in the art to variouslyemploy the methods and structures of the present disclosure. Forpurposes of the description hereinafter, the terms “upper”, “lower”,“vertical”, “horizontal”, “top”, “bottom”, “width”, “length”,“thickness” and derivatives thereof shall relate to the disclosedstructures and methods, as oriented in the drawing figures.

In some embodiments, the methods and structures disclosed hereinovercome misalignment between masks for forming conductive features inan integrated circuit. In some embodiments, the conductive featuresinclude lines and vias. The lines are the conductive pathways thatextend across, i.e., have a longest dimension across, the horizontalplane of the substrate. The horizontal plane is parallel to the planedefined by the upper surface of the substrate. The vias are theconductive pathways that extend along, e.g., have a longest dimensionalong, the vertical plane of the substrate. The vertical plane of thesubstrate is perpendicular to the horizontal plane of the substrate,wherein the vertical plane extends along the depth dimension of thesubstrate. In some embodiments, the conductive features may be more thanone set of lines, wherein each set of lines has a length that spansacross a different direction.

In some embodiments, the disclosed methods and structures fill theunintended etch features, i.e., sliver openings, that are created byetching the substrate with etch masks including vias openings thatoverlap with line openings. The misalignment between the masks may bethe result of inherent variations of the photolithography process thatforms the masks. For example, the mask misalignment may include at leastone of the following phenomena: mask writing errors, magnificationerrors, tool misregistration, thermal expansion, or a combinationthereof. The unintended etch feature when filled during the metaldeposition steps for forming the lines and vias can become an undesiredvia, which in some instances can result in shorting adjacent lines orlines between levels. In some embodiments, to overcome the formation ofthe undesired vias, the unintended etch features, i.e., sliver openings,are filled with a selective etch material (also referred to as a fillmaterial). After the unintended etch features, i.e., sliver openings,are filled, the etch process for forming the vias and lines may becontinued with an etch process that is selective to the selective etchmaterial that is present in the sliver openings. In some embodiments,because the sliver openings are filled with the selective etch material,subsequent etch process can not extend the depth of the sliver openingsto a greater depth within the substrate. In other embodiments, theportions of the line openings and via openings that overlap, i.e.,shared openings, in the mask may be filled with a selective etchmaterial before etching the underlying substrate. FIGS. 1-10D depictsome embodiments of a method for reducing the effects of misalignmentbetween mask openings for forming lines and vias.

FIG. 1 depicts one embodiment of forming a first mask layer 15 of a maskfor forming lines and vias in a substrate 10. In one embodiment, thefirst mask layer 15 is patterned the to correspond to lines that are tobe etched into the substrate 10. The substrate 10 may be composed of adielectric or semiconductor material. In the embodiment that is depictedin FIG. 1, the substrate 10 may include an interlevel dielectric layer 5and a base semiconductor substrate 1. The interlevel dielectric layer 5may include any dielectric material. For example, the interleveldielectric layer 5 may be selected from the group consisting ofsilicon-containing materials, such as SiO₂, Si₃N₄, SiO_(x)N_(y), SiC,SiCO, SiCOH, and SiCH compounds, the above-mentioned silicon-containingmaterials with some or all of the Si replaced by Ge, carbon-dopedoxides, inorganic oxides, inorganic polymers, hybrid polymers, organicpolymers such as polyamides or SILK™, other carbon-containing materials,organo-inorganic materials such as spin-on glasses andsilsesquioxane-based materials, and diamond-like carbon (DLC, also knownas amorphous hydrogenated carbon, α-C:H). Additional choices for theinterlevel dielectric layer 5 include any of the aforementionedmaterials in porous form, or in a form that changes during processing toor from being porous and/or permeable to being non-porous and/ornon-permeable.

The interlevel dielectric 5 that is depicted in FIG. 1 may be present ona base semiconductor substrate 1. The base semiconductor substrate 1 maybe any silicon-containing substrate including, but not limited to, Si,bulk Si, single crystal Si, polycrystalline Si, SiGe, amorphous Si,silicon-on-insulator substrates (SOI), SiGe-on-insulator (SGOI),strained-silicon-on-insulator, annealed poly Si, and poly Si linestructures. The base semiconductor substrate 1 may also be composed ofcompound semiconductor materials, such as a type III-V semiconductor.The base semiconductor substrate 1 may include conductive lines,semiconductor devices or memory devices formed within the basesemiconductor substrate 1 and/or on the base semiconductor substrate 1.Although FIG. 1 depicts a conductive line 2 that can be formed in thebase semiconductor substrate 1, the present disclosure is not limited toonly this example. Examples of semiconductor devices that may be presenton the base semiconductor substrate 1 include complementary metal oxidesemiconductor (CMOS) devices, fin field effect transistors (finFETs),junction field effect transistors (JFETs), bipolar junction transistor(BJTs) or a combination thereof. Examples of memory devices that may bepresent on or formed within the base semiconductor substrate 1 includeembedded dynamic random access memory or flash memory. The basesemiconductor substrate 1 may include any electrical device that can beelectrically contacted by a via that can be extending through theinterlevel dielectric layer 5. The substrate 10 that is depicted in FIG.1 is only one example of a substrate 10 that may be suitable for usewith the methods and structures disclosed herein.

The first mask layer 15 may be patterned to correspond to lines that areto be etched into the substrate 10. The first mask layer 15 may be ahard mask. The hard mask may be composed of metallic material such asTiN. In other embodiments, first mask layer 15 may be composed ofdielectric material including, but not limited to, oxides, nitrides oroxynitride dielectrics, in which the dielectric material is a differentdielectric material than the interlevel dielectric layer 5. Hard maskmaterials may also include dielectric systems that may be deposited bychemical vapor deposition (CVD) and related methods. Spin-on dielectricsmay also be utilized as a hard mask material including, but not limitedto: silsequioxanes, siloxanes, and boron phosphate silicate glass(BPSG). In the embodiments, in which the hardmask material is adielectric, the hard mask material that is deposited on the substrate 10may be referred to as a first dielectric layer.

The first mask layer 15 of the hard mask material may be formed byblanket depositing a layer of hard mask material followed by patterningusing photolithography and etch processes. In one embodiment, the hardmask material may be deposited using chemical vapor deposition (CVD).Examples of chemical vapor deposition methods that are suitable forforming the hard mask material include, but not limited to, AtmosphericPressure CVD (APCVD), Low Pressure CVD (LPCVD) and Plasma Enhanced CVD(PECVD), Metal-Organic CVD (MOCVD) and combinations thereof may also beemployed. The hard mask material may also be deposited usingevaporation, chemical solution deposition, spin on deposition, andphysical vapor deposition (PVD) methods. The hard mask material may havea thickness ranging from 5 nm to 90 nm. In another embodiment, the hardmask material may have a thickness ranging from 10 nm to 30 nm.

Following deposition, the blanket layer of hard mask material may bepatterned using photolithography and etch processes, in which theopenings formed in the layer of the hard mask material are selected tocorrespond with the subsequently formed lines in the substrate 10. Inone embodiment, a layer of photoresist material is applied atop thelayer of hard mask material via spin coating or similar processes. Thephotoresist material may be comprised of a dielectric material includingcarbon, oxygen, and various inorganic materials. Following applicationof the photoresist layer, the photoresist is soft-baked, where thesolvents of the photoresist layer are evaporated via heating. The layerof photoresist is then patterned using a photolithography process. Forexample, a pattern is formed using a reticle or photomask andtransferred into the layer of photoresist on the surface to be etched.Light is passed through the opaque pattern of the reticle, which in turnproduces a patterned image on the layer of photoresist. The photoresistlayer is a light or radiation sensitive material and exposure to lightcauses changes in the photoresist structure. For example, exposure tolight may change the exposed portions of the photoresist from a solublecondition to an insoluble one.

Following exposure, the pattern is developed utilizing a resistdeveloper, such as a chemical solvent. The developer leaves a hole inthe resist layer that corresponds to the opaque pattern of the reticle.An alternative resist strategy, commonly referred to as a negativeresist, leaves a pattern in the resist opposite to that on the mask.Development of the pattern is conducted using development techniquesincluding, but not limited to: continuous spray development and puddledevelopment. Following development of the patterned photoresist layer aphotoresist mask is formed.

Following formation of the photoresist mask over the layer of hard maskmaterial, an etch process is employed to etch the hard mask materialselectively to the photoresist mask and the underlying substrate 10,i.e., interlevel dielectric layer 5. As used herein, the term“selective” in reference to a material removal process denotes that therate of material removal for a first material is greater than the rateof removal for at least another material of the structure to which thematerial removal process is being applied. For example, a selective etchmay remove one material to a second material at a rate that is greaterthan 10:1. In another example, a selective etch may remove one materialto a second material at a rate that is greater than 100:1

In one embodiment, the etch process that etches the hard mask materialto provide the first mask layer 15 is an anisotropic etch. Ananisotropic etch process is a material removal process in which the etchrate in the direction normal to the surface to be etched is greater thanin the direction parallel to the surface to be etched. The anisotropicetch may include reactive-ion etching (RIE). Other examples ofanisotropic etching that can be used at this point of the presentdisclosure include ion beam etching, plasma etching or laser ablation.

In one embodiment, the openings that are forming in the first mask layer15 may have a width W1, W2, W3 ranging from 14 nm to 80 nm. In anotherembodiment, the openings that are formed in the first mask layer 15 mayhave a width W1, W2, W3 ranging from 10 nm to 80 nm. The pitchseparating adjacent openings in the first mask layer 15 may range from14 nm to 80 nm. In another embodiment, the pitch separating adjacentopenings in the first mask layer 15 may range from 10 nm to 80 nm.

FIG. 1 further depicts one embodiment of forming a second mask layer 20on the substrate 10. In some embodiments, the combination of the firstmask layer 15 and the second mask layer 20 functions as a first etchmask for a first etch process of the substrate 10. After the first etchprocess, the second mask layer 20 can be removed and the remaining firstmask layer 15 can function as a second etch mask for etching thesubstrate 10 with a second etch process.

In one embodiment, the second mask layer 20 is patterned to correspondto vias that are to be etched into the substrate 10, e.g., interleveldielectric layer 5. The second etch mask 20 may be composed of aphotoresist. The photoresist mask that provides the second etch mask 20is similar to the photoresist mask that is used to form the first etchmask 15, as described above. For example, the photoresist mask thatprovides the second etch mask 20 may be formed by applying a photoresistto the surface to be etched, exposing the photoresist to a pattern ofradiation, and then developing the pattern into the photoresistutilizing resist developer. Once the patterning of the photoresist iscompleted, the sections covered by the photoresist are protected whilethe exposed regions are removed using a selective etching process thatremoves the unprotected regions. In other embodiments, the second mask20 is composed of a hard mask material that is similar to the first etchmask 15, but is typically composed of a material having a different etchselectivity as the first etch mask 15.

In one embodiment, the openings that are forming in the second masklayer 20 may have a width W4 ranging from 14 nm to 80 nm. In anotherembodiment, the openings that are forming in the second mask layer 20may have a width W4 ranging from 20 nm to 28 nm. The vias that areformed using the mask arrangements disclosed herein may have arectangular or square cross section when view from a top downperspective. The length dimension of the vias formed by the maskarrangements disclosed herein may range from 1.0 to 2.0 times the widthdimension (10 nm to 150 nm), and the width dimension of the vias mayrange from 10 nm to 80 nm. In another embodiment, length dimension ofthe vias may range from 14 nm to 56 nm, and the width dimension of thevias may range from 14 nm to 112 nm. In another embodiment, the openingsthat are formed in the second mask layer 20 may be circular.

In one embodiment, the combination of the first mask layer 15 and thesecond mask layer 20 are configured to provide a first opening in thesubstrate 10, e.g., interlevel dielectric 5, that when extended throughthe interlevel dielectric 5 provides a via. The first opening is formedin the exposed portion of the substrate 10, which is the intendedpattern that is provided by the first and second mask layers 15, 20. Thefirst mask layer 15 and the second mask layer 20 may be misaligned toform a shared opening region 25. The shared opening region 25 exposes aportion of the substrate 10 that is not intended to be etched by theetch process that forms at least one of a line or an array. The sourceof misalignment between the first mask layer 15 and the second masklayer 20 may include at least one of the following phenomena: maskwriting errors, magnification errors, tool misregistration, thermalexpansion, or a combination thereof. In one embodiment, the sharedopening region 25 has a width W5 less than 25 nm. In another embodiment,the shared opening region 25 has a width W5 less than 8 nm.

FIG. 2 depicts one embodiment of first etching the substrate 10, e.g.,interlevel dielectric 5, using the first mask layer 15 and the secondmask layer 20 as a first etch mask. In some embodiments, the firstetching forms a first opening 30 to a first depth D1 into the substrate10, and the shared opening region 25 between the first mask layer 15 andthe second mask layer 20 forms a sliver opening 35 in the substrate 10,e.g., interlevel dielectric layer 5. The first etching that forms thefirst opening 30 and the sliver opening 35 may be provided by ananisotropic etch process. The anisotropic etch may include reactive-ionetching (RIE). In some embodiments, reactive ion etch (RIE) is a form ofplasma etching, in which the surface to be etched may be placed on an RFpowered electrode and takes on a potential that accelerates an etchingspecies, which is extracted from a plasma, towards the surface to beetched, wherein a chemical etching reaction takes place in the directionnormal to the surface being etched. Other examples of anisotropicetching that can be used at this point of the present disclosure includeion beam etching, plasma etching or laser ablation. The first etchingmay be provided by a selective etch. For example, in one embodiment, theetch process employed to form the first opening 30, which also can formthe sliver opening 35, may remove the material of the substrate 10,e.g., interlevel dielectric layer 5, selectively to the first mask layer15 and the second mask layer 20.

The first etching process may be a timed etch. The first etch may becontinued until the base of the first opening 30 that is extended intothe interlevel dielectric layer 5 reaches a depth ranging from 25 nm to400 nm, as measured from the upper surface of the interlevel dielectriclayer 5. In another embodiment, the first etch may be continued untilthe base of the first opening 30 that is extended into the interleveldielectric layer 5 reaches a depth D1 ranging from 40 nm to 200 nm, asmeasured from the upper surface of the interlevel dielectric layer 5.The sliver opening 35 can be formed at the same time as the firstopening, and can formed by a misalignment of the first mask layer 15 andthe second mask layer 20. Because the sliver opening 35 and the firstopening 30 are both formed in the same interlevel dielectric, and thesliver opening 35 and the first opening 30 are both formed with thefirst and second mask layers 15, 20, the sliver opening 35 and the firstopening 30 may both be formed to approximately the same depth within thesubstrate 10, i.e., interlevel dielectric layer 5.

FIG. 3 depicts one embodiment of removing the second mask layer 20. Inone embodiment, the second mask layer 20 may be removed using oxygenashing, chemical stripping or selective etching. For example, in oneembodiment, the second mask layer 20 may be removed by an etch that isselective to the substrate 10, e.g., interlevel dielectric layer 5, andthe first mask layer 15. In some embodiments, in which the combinationof first mask layer 15 and the second mask layer 20 provide a first etchmask, removing the second mask layer 20 provides a second etch mask thatmay be composed only of the first mask layer 15.

FIG. 4 depicts one embodiment of conformally depositing a material layerto fill the sliver opening 35 with the material for selective etching40. The material for selective etching 40 is a material that is notetched by an etch process that removes the material of the substrate 10,e.g., interlevel dielectric layer 5. The material for selective etching40 is interchangeably referred to as the fill material 40. In oneembodiment, the selective etch material 40 may be a dielectric material,such as an oxide, nitride, or oxynitride. In some embodiments, theselective etch material 40 may be at least one of SiO₂, Si₃N₄,SiO_(x)N_(y), SiC, SiCO, SiCOH, and SiCH compounds, the above-mentionedsilicon-containing materials with some or all of the Si replaced by Ge,carbon-doped oxides, inorganic oxides, inorganic polymers, hybridpolymers, organic polymers such as polyamides or SiLK™, othercarbon-containing materials, organo-inorganic materials such as spin-onglasses and silsesquioxane-based materials, and diamond-like carbon(DLC, also known as amorphous hydrogenated carbon, α-C:H). In theembodiments, in which the selective etch material 40 is a dielectricmaterial, the selective etch material 40 may be referred to as a seconddielectric layer. The selective etch material 40 can alternatively be asemiconductor material. It is noted that it is not intended that thepresent disclosure be limited to only the above material compositionsfor the selective etch material 40. For example, the selective etchmaterial 40 may be any material that the substrate 10, e.g., interleveldielectric layer 5, can be selectively etched to. For example, materialsthat the substrate 10 can be etched to at a ratio of 5:1 or greater canbe suitable for the selective etch material 40. In another example,materials that the substrate 10 can be etched to at a ratio of 100:1 orgreater can be suitable for the selective etch material 40.

In some embodiments, the selective etch material 40 may be a conformallayer that is blanket deposited over the substrate 10 including thefirst mask layer 15, first opening 30, and the sliver opening 35 using aconformal deposition process. The term “conformal” denotes a layerhaving a thickness that does not deviate from greater than or less than20% of an average value for the thickness of the layer. The selectiveetch material 40 may be deposited using chemical vapor deposition (CVD).Chemical vapor deposition (CVD) is a deposition process in which adeposited species is formed as a result of chemical reaction betweengaseous reactants at an elevated temperature (typically greater than200° C.), wherein a solid product of the reaction is deposited on thesurface on which a film, coating, or layer of the solid product is to beformed. Variations of CVD processes include, but not limited to,Atmospheric Pressure CVD (APCVD), Low Pressure CVD (LPCVD) and PlasmaEnhanced CVD (EPCVD), Metal-Organic CVD (MOCVD) and combinations thereofmay also be employed. The selective etch material 40 may also bedeposited using evaporation, chemical solution deposition, spin ondeposition, and physical vapor deposition (PVD) methods.

The thickness of the selective etch material 40, i.e., fill material, isselected so that it fills the sliver opening 35. More specifically, inone embodiment, the selective etch material 40 is deposited so that afirst portion of the material layer of the selective etch material 40that is deposited on the first opening 30 has a first thickness T1, anda second portion of the material layer of the selective etch material 40that is present in the sliver opening 35 has a second thickness T2 thatfills the sliver opening 35. In one embodiment, the selective etchmaterial 40 is deposited to have a thickness that is between 5/16^(th)the width W6 of the sliver opening 35 and 11/16^(th) the width W6 of thesliver opening 35. In another embodiment, the selective etch material 40is deposited to have a thickness that is between ⅜^(th) the width W6 ofthe sliver opening 35 and ⅝^(th) the width W6 of the sliver opening. Inone example, the selective etch material 40 is deposited to have athickness that is between ⅜^(th) the width W6 of the sliver opening 35and ⅝^(th) the width W6 of the sliver opening 35. Although, theselective etch material 40 is typically deposited using a conformaldeposition method, the portion of the selective etch material 40 that ispresent in the sliver opening 35 has a greater thickness than theremaining portions of the selective etch material 40 that is not presentin the sliver opening 35, because the selective etch material 40 isfilling the sliver opening 35 from both sidewall surfaces.

FIG. 5 depicts one embodiment of isotropically etching the selectiveetch material to remove a first portion of the material layer of theselective etch material, in which a second portion of the material layerof the selective etch material 40 a remains in the sliver opening 35.The first portion of the material layer of the selective etch materialis the portion that is present in the first openings 30 and is presenton the first mask layer 15, but is not present within the sliver opening35. One example of an isotropic etch is a wet chemical etch. In anotherembodiment, the isotropic etch process may be a plasma etch, wet etch,or a combination thereof. In one embodiment, in which the selective etchmaterial is composed of silicon nitride (SiO₂), the upper surface of thesubstrate 10, e.g., interlevel dielectric 5, is SiCOH, and the firstmask layer 15 is composed of TiN, the wet etch chemistry for removingthe first portion of the material layer of the selective etch material40 a may be composed of dilute HF or buffered HF. The portion of theselective etch material 40 a that remains in the sliver opening 35 afterthe isotropic etch that removes the selective etch material from atleast the first opening 30 is hereafter referred to as a sliver fill 40a.

FIG. 6 depicts one embodiment of second etching the substrate 10, e.g.,the interlevel dielectric 5, using only the first mask layer 15 as asecond etch mask with an etch that is selective to the first mask layer15 and the selective etch material that fills the sliver opening, i.e.,sliver fill material 40 a. In one embodiment, the second etching of thesubstrate 10, e.g., the interlevel dielectric layer 5, with the firstmask layer 15 as a second etch mask extends the first opening 30 a to asecond depth D2 to provide openings 30 a for the vias. In oneembodiment, the second depth D2 ranges from 50 nm to 500 nm. In anotherembodiment, the second depth D2 ranges from 75 nm to 200 nm. In oneembodiment, the first opening 30 a is extended to a second depth D2 thatextends through the entire thickness of the interlevel dielectric layer5 to another line 2 that is present in the base semiconductor substrate1 that is underlying interlevel dielectric layer 5. In anotherembodiment, the first opening 30 a is extended through the entirethickness of the interlevel dielectric layer 5 to a semiconductordevice, or memory device (not depicted), that is present in theunderlying base semiconductor substrate 1. The openings 30 a for thevias are hereafter referred to as via openings 30 a.

The second etching of the substrate 10, e.g., the interlevel dielectriclayer 5, using the first mask layer 15 as the etch mask also forms theopenings for the lines 30 b, 45. The openings for the lines 30 b, 45 arehereafter referred to as line openings 30 b, 45. In one embodiment, theline openings 30 b, 45 are provided by the portion 30 b of the firstopening that extends to the first depth D1 and a separate second opening45 that is etched into the substrate 10, e.g., interlevel dielectric 5,at a depth D3 that is less than the second depth D2 of the via openings30 a. In one embodiment, the line openings identified by referencenumbers 30 b and 45 have the same depth. In one embodiment, the depth D3of the line openings 45 that are patterned using only the first masklayer 15 may range from 30 nm to 400 nm. In one embodiment, the depth D3of the line openings 45 that are patterned using only the first masklayer 15 may range from 40 nm to 150 nm

In one embodiment, the second etching of the substrate 10 is provided byan anisotropic etch process. Examples of anisotropic etch processes thatare suitable for this stage of the present disclosure include reactiveion etch (RIE), ion beam etching, laser ablation or a combinationthereof. The etch method for the second etch of the substrate 10typically has an etch chemistry that removes the material of thesubstrate 10, i.e., interlevel dielectric layer 5, selectively to thefirst mask layer 15 and the sliver fill 40 a. In some embodiments,because the sliver fill 40 a is present in the sliver opening, and thesecond etch is selective to the sliver fill 40 a, the sliver fill 40 aobstructs the second etch from extending the sliver opening to a furtherdepth within the substrate 10, e.g., interlevel dielectric layer 5. Inone embodiment, in which the sliver fill 40 a is composed of SiO₂, thesubstrate 10, e.g., interlevel dielectric 5, is SiCOH, and the firstmask layer 15 is composed of TiN.

FIG. 7 depicts one embodiment of removing the sliver fill 40 a after thesecond etch of the substrate 10, e.g., interlevel dielectric layer 5.The sliver fill 40 a may be removed by an etch that is selective to atleast the substrate 10, e.g., interlevel dielectric layer 5, andoptionally may be selective to the first mask layer 15. The etch processfor removing the sliver fill 40 a may be an anisotropic etch, such asreactive ion etch (RIE) or an isotropic etch, such as a wet chemicaletch. In some embodiments, removing the sliver fill 40 a forms a pinchregion 41 on at least one sidewall of the line opening 45. The base B1of the pinch region 41 is in direct contact with the base of the sliverfill 40 a after the second etch forms the second openings 45 and beforethe sliver fill 40 a is removed. If the first depth D1 is smaller thanthe depth D3 of the second opening then the pinch region 41 has a basesurface B1 at a lesser depth within the substrate 10, e.g., interleveldielectric layer 5, than the depth of the base B2 of the second opening45 that is formed by the second etch. In one embodiment, the basesurface B1 of the pinch region 41 is vertically offset from the base B2of the second opening 45 by a dimension ranging from 0 nm to 100 nm. Inanother embodiment, the base surface B1 of the pinch region 41 isvertically offset from the base B2 of the second opening 45 by adimension ranging from 5 nm to 15 nm.

FIG. 8 depicts another embodiment of removing the sliver fill 40 a. Inthe embodiment that is depicted in FIG. 8, the second etch of thesubstrate 10 that is described above with reference to FIG. 6 forforming the via openings 30 a and the line openings 45 in the interleveldielectric layer 5 also removes the sliver fill 40 a. In thisembodiment, the etch for forming the via openings 30 a and the lineopenings 45 is not selective to the sliver fill 40 a. In this embodimenta pinch region is not formed in the sidewalls of the line openings 45,but a dimple region 42 may be formed. The dimple region 42 may be formedby an over etch of the sliver fill 40 a. The dimple region 42 has a basesurface B3 at a greater depth within the substrate 10, e.g., interleveldielectric 5, than the depth of the base B4 of the second opening 45that is formed by the second etch. In one embodiment, the base surfaceB3 of the dimple region 42 is vertically offset from the base B4 of thesecond opening 45 by a dimension ranging from 0 nm to 20 nm. In anotherembodiment, the base surface B3 of the dimple region 42 is verticallyoffset from the base B5 of the second opening 45 by a dimension rangingfrom 5 nm to 10 nm.

FIG. 9 depicts another embodiment of the present disclosure that doesnot employ the isotropic etch that is applied to the sliver fill 40(described above as a selective etch material) that is described abovewith reference to FIGS. 4 and 5. More specifically, following theformation of the sliver fill 40 depicted in FIG. 4, the second etch isapplied to the substrate 10, e.g., interlevel dielectric layer 5, thatis described with reference to FIG. 6, without applying the isotropicetch that is described with reference to FIG. 5. In the embodiment thatis depicted in FIG. 9, the second etch of the substrate 5, e.g.,interlevel dielectric 5, also removes the sliver fill 40. In thisembodiment, if the second etch of the substrate 10, e.g., interleveldielectric layer 5, removes the sliver fill 40 at the same rate as thesubstrate 10 material, e.g., interlevel dielectric layer 5, the viaswill shrink compared to the lines by approximately twice thewidth/thickness of the sliver fill. Shoulders 43 may also be present atthe base of the lines.

Removing the sliver fill 40 a is optional. In some embodiments, thesliver fill 40 a may remain in the final integrated circuit (IC)structure. For example, the sliver fill 40 a may fill the dimple, pinchregion and/or extend along the sidewall of said at least one of theconductive line.

FIGS. 10A-10CD depict filling the via openings 30 a and the lineopenings 30 b, 45 with a conductive material. The term “conductive”denotes a room temperature conductivity greater than about 10⁻¹⁰(Ω-m)⁻¹. Filling the via openings 30 a and the line openings 30 b, 45with a conductive material forms vias 50 and lines 55. In oneembodiment, the conductive material may be a metal. Metals that aresuitable for forming the vias 50 and the lines 55 may include aluminum(Al), copper (Cu), titanium (Ti), tungsten (W), tantalum (Ta), platinum(Pt) and a combination thereof. The conductive material, e.g., metal,may be deposited in the via openings 30 a and the line openings 30 b, 45using a physical vapor deposition (PVD) method, plating, andevaporation. Examples of sputtering apparatus that may be suitable fordepositing the conductive material for the vias 50 and the lines 55include DC diode type systems, radio frequency (RF) sputtering,magnetron sputtering, and ionized metal plasma (IMP) sputtering. Inanother embodiment, the vias 50 and the lines 55 are formed using adeposition process, such as chemical vapor deposition (CVD). Variationsof chemical vapor deposition (CVD) processes for depositing the vias 50and the lines 55 include, but are not limited to, Atmospheric PressureCVD (APCVD), Low Pressure CVD (LPCVD) and Plasma Enhanced CVD (PECVD),Metal-Organic CVD (MOCVD) and others.

FIG. 10A depicts one embodiment of the present disclosure in which atleast one of the vias 55 contacts an underlying line 2 that is presentin the base semiconductor substrate 1. FIG. 10C depicts one embodimentthe present disclosure in which at least one of the vias 55 contacts anunderlying semiconductor device 65 that is present in the basesemiconductor substrate 1. Examples of semiconductor devices 65 that maybe present on the semiconductor substrate 1 include complementary metaloxide semiconductor (CMOS) devices, fin field effect transistors(finFETs), junction field effect transistors (JFETs), bipolar junctiontransistor (BJTs) or a combination thereof. FIG. 10D depicts oneembodiment of the present disclosure in which a pinch region 41 ispresent at the interface of the base of a conductive line and a sidewallof a conductive line. FIG. 10E depicts one embodiment of the presentdisclosure in which the sliver fill 40 a is not removed prior to fillingthe line openings with a conductive material, such as a metal.

FIGS. 1 and 11-15 depict another embodiment of the present disclosure,in which a shared opening region 25 that can result from misalignmentbetween masks for forming the vias 50 and lines 55 is filled with aconformal fill layer 70 before etching the substrate 10, e.g.,interlevel dielectric layer 5. Referring to FIG. 1, in one embodiment,the method may begin with forming a first mask layer 15 on a substrate10, e.g., interlevel dielectric layer 5, that is patterned to correspondto lines. FIG. 1 further depicts one embodiment of forming a second masklayer 20 on the substrate 10, e.g., interlevel dielectric layer 5, overthe first mask layer 15. The combination of the first mask layer 15 andthe second mask layer 20 provide a pattern that corresponds to the viasand a shared opening region 25 is present between openings in the firstmask layer 15 and the second mask layer 20. The first mask layer 15 andthe second mask layer 20 that have been described above with referenceto the embodiments depicted in FIGS. 1-10B are similar to the first masklayer 15 and the second mask layer 20 that are described with referenceto the embodiments of the present disclosure that are consistent withthe process flow depicted in FIGS. 1 and 11-15. Therefore, the abovedescription of the first mask layer 15 and the second mask layer 20, aswell as the base semiconductor substrate 1, and the interleveldielectric layer 5, is suitable for these elements in the methoddescribed with reference to FIGS. 1 and 11-15.

FIG. 11 depicts one embodiment of depositing a conformal fill layer 70on the structure depicted in FIG. 1. The material for the conformal filllayer 70 is a material that is not etched by an etch process thatremoves the material of the substrate 10, e.g., interlevel dielectric 5.In one embodiment, the conformal fill layer 70 may be a dielectricmaterial, such as an oxide, nitride, or oxynitride. In some embodiments,the conformal fill layer 70 may be at least one of SiO₂, Si₃N₄,SiO_(x)N_(y), SiC, SiCO, SiCOH, and SiCH compounds, the above-mentionedsilicon-containing materials with some or all of the Si replaced by Ge,carbon-doped oxides, inorganic oxides, inorganic polymers, hybridpolymers, organic polymers such as polyamides, other carbon-containingmaterials, organo-inorganic materials such as spin-on glasses andsilsesquioxane-based materials, and diamond-like carbon (DLC, also knownas amorphous hydrogenated carbon, α-C:H). The conformal fill layer 70may also be composed of a semiconductor material. It is noted that it isnot intended that the present disclosure be limited to only the abovematerial compositions for the conformal fill layer 70. For example, theconformal fill layer 70 may be any material that the substrate 10, e.g.,interlevel dielectric layer 5, can be selectively etched to. Forexample, materials that the substrate 10 can be etched to at a ratio of10:1 or greater can be suitable for the conformal fill layer 70. Inanother example, materials that the substrate 10 can be etched to at aratio of 100:1 or greater can be suitable for the conformal fill layer70.

The conformal fill layer 70 may be deposited using chemical vapordeposition (CVD). Variations of CVD processes include, but not limitedto, Atmospheric Pressure CVD (APCVD), Low Pressure CVD (LPCVD) andPlasma Enhanced CVD (EPCVD), Metal-Organic CVD (MOCVD) and combinationsthereof may also be employed. The conformal fill layer 70 may also bedeposited using evaporation, chemical solution deposition, and physicalvapor deposition (PVD) methods.

The thickness of the conformal fill layer 70 is selected so that aconformally deposited layer will fill the shared opening region 25. Afirst portion of the conformal fill layer 70 that is deposited in theshared opening region 25 has a first thickness T3, and a remainingportion of the conformal fill layer 70 that is present on the first masklayer 15, second mask layer 20 and the substrate 10, e.g., interleveldielectric layer 5, has a second thickness T4. The first thickness T3 ofthe conformal fill layer 70 that is present in the shared opening region25 is greater than the second thickness T4 of the conformal fill layer70 that is not present in the shared opening region 25. Although, theconformal fill layer 70 is typically deposited using a conformaldeposition method, the portion of the conformal fill layer 70 that ispresent in the shared opening region 25 has a greater thickness than theremaining portions of the conformal fill layer 70 that is not present inthe shared opening region 25, because the conformal fill layer 70 isfilling the shared opening region 25 side surfaces. The first thicknessT3 of the conformal fill layer 70 may range from 5 nm to 90 nm, and thesecond thickness T4 of the conformal fill layer 70 may range from 4 nmto 20 nm. In another embodiment, the first thickness T3 of the conformalfill layer 70 may range from 10 nm to 30 nm, and the second thickness T4of the conformal fill layer 70 may range from 6 nm to 9 nm.

FIG. 12 depicts one embodiment of isotropically etching the conformalfill layer 70 to remove the remaining portion of the conformal filllayer that is not present in the shared opening region 25, wherein thefirst portion of the conformal fill layer 70′ remains in the sharedopening region 25. One example of an isotropic etch that is suitable forremoving the first portion of the conformal fill layer is a wet chemicaletch. The isotropic etch process for removing the first portion of theconformal fill layer may be a plasma etch, dry chemical etch, or acombination thereof. In one embodiment, in which the conformal filllayer is composed of SiO₂, the upper surface of the substrate 10, e.g.,interlevel dielectric 5, is SiCOH, and the first mask layer 15 iscomposed of TiN, the wet etch chemistry for removing the first portionof the conformal fill layer may be composed of dilute HF or buffered HFof sufficient time and concentration to remove 120-140% of the thicknessT4 of conformal fill layer 70.

FIG. 12 also depicts first etching the substrate 10, e.g., interleveldielectric layer 5, using the first mask layer 15, the second mask layer20, and the remaining portion of the conformal fill layer 70′ that ispresent in the shared opening region 25 as a first etch mask. The firstetching of the substrate 10, e.g., interlevel dielectric layer 5, formsa first opening 30′ to a first depth D4 into the substrate 10, e.g.,interlevel dielectric layer 5. The first etching that forms the firstopening 30′ may be provided by an anisotropic etch process. Theanisotropic etch may include reactive-ion etching (RIE). Other examplesof anisotropic etching that can be used at this point of the presentdisclosure include ion beam etching, or laser ablation. The firstetching may be provided by a selective etch. For example, in oneembodiment, the etch process employed to form the first opening 30′, mayremove the material of the substrate 10, e.g., interlevel dielectriclayer 5, selectively to the first mask layer 15, the remaining portionof the conformal fill layer 70′, and the second mask layer 20. The firstetching process may be a timed etch. The first etch may be continueduntil the base of the first opening 30 that is extended into theinterlevel dielectric layer 5 reaches a depth D4 ranging from 25 nm to400 nm, as measured from the upper surface of the interlevel dielectriclayer 5. In another embodiment, the first etch may be continued untilthe base of the first opening 30′ that is extended into the interleveldielectric layer 5 reaches a depth D4 ranging from 25 nm to 400 nm, asmeasured from the upper surface of the interlevel dielectric layer 5.

FIG. 13 depicts removing the second mask and the portion of theconformal fill layer that was present in the shared opening region. Inone embodiment, the second mask may be removed using oxygen ashing,chemical stripping or selective etching. In one embodiment, theremaining portion of the conformal fill layer may be removed byselective etching. For example, in one embodiment, the second mask andthe remaining portion of the conformal fill layer may be removed by anetch that is selective to the substrate 10, e.g., interlevel dielectriclayer 5, and the first mask layer 15.

FIG. 14 depicts one embodiment of second etching the substrate 10, e.g.,interlevel dielectric layer 5, using the only the first mask layer 15 asa second etch mask. In one embodiment, the second etching of thesubstrate 10 using the first mask layer 15 as a second etch mask extendsthe first opening to a second depth D5 to provide openings 30 a′ for thevias. In one embodiment, the second depth D5 ranges from 50 nm to 500nm. In another embodiment, the second depth D5 ranges from 75 nm to 200nm. The openings for the vias 30 a′ are hereafter referred to as viaopenings 30 a′.

In one embodiment, the second etching of the substrate 10 is provided byan anisotropic etch process. Examples of anisotropic etch processes thatare suitable for this stage of the present disclosure include reactiveion etch (RIE), ion beam etching, laser ablation or a combinationthereof.

The second etching of the substrate 10, e.g., the interlevel dielectric5, using the first mask layer 15 as the etch mask also forms theopenings for the lines 30 b′, 45′. The openings for the lines 30 b′, 45′are hereafter referred to as line openings 30 b′, 45′. In oneembodiment, the line openings 30 b′, 45′ are provided by the portion 30b′ of the first opening that extends to the first depth D4 and a secondopening 45′ that is etched into the substrate 10, e.g., interleveldielectric 5, at a depth D6 that is less than the second depth D5 of thevia openings 30 a′. In one embodiment, the depth D6 of the line openings45′ may range from 30 nm to 400 nm. In one embodiment, the depth D6 ofthe line openings 45′ may range from 40 nm to 150 nm.

Following second etching of the substrate 10, the at least one of theopenings for the vias 30 a′ and the openings for the lines 30 b′, 45′may be filled with a conductive material. Filling the openings for thevias 30 a′ and the openings for the lines 30 b′, 45′ with a conductivematerial, such as a metal, has been described above with reference toFIGS. 10A and 10B. The description of the vias 50 and lines 55 that areillustrated in FIGS. 10A and 10B are suitable for the vias and linesthat are formed using the method described with reference to FIGS. 1 and11-14.

Referring to FIG. 10A-10E, in one embodiment, an array of conductivepathways is provided that includes a substrate 10 comprised of adielectric material, e.g., an interlevel dielectric layer 5, and anarray of conductive lines 55 at a first depth within the substrate 10.Each of the conductive lines 55 in the array of conductive lines has alength that extends along a horizontal direction of the substrate 10 andis substantially parallel to a plane defined by an upper surface of thesubstrate. In one embodiment, at least one of the conductive lines 55has a dimple region 42 on the sidewall of the at least one conductiveline 55, and at a lower surface of the at least one of the conductiveline 55, as depicted in FIG. 10A. In another embodiment, the at leastone of the conductive line 55 has a pinch region 41 on the sidewall ofthe at least one conductive line 55, and at a lower surface of the atleast one of the conductive line 55, as depicted in FIG. 10D. In yetanother embodiment, a sliver fill 40 a is present along the sidewall ofthe at least one conductive line 55. In another embodiment, the dimpleregion 42 and/or the pinch region 41 are not present in the finalstructure. An array of vias 50 intersect with the array of conductivelines 55. Each of the vias 50 is above or below the first depth withinthe substrate 10. Each of the vias 50 has a vertical dimension that isperpendicular to the length of each of the conductive lines 55.

Although the conductive features that are etched into the substrate havebeen described above as including both vias and lines, embodiments havebeen contemplated in which the first mask layer 15 and the second masklayer 20 are patterned to provide two sets of lines having differentdirections. For example, the first mask layer 15 and the second masklayer 20 may be employed together to form a first etch feature, e.g.,first set of lines having a first direction, wherein one of the firstmask layer 15 and the second mask layer 20 may be removed in combinationwith a second etch process to form a second etch feature, e.g. secondset of lines having a second direction. In one example, the firstdirection of the first set of lines is substantially perpendicular tothe second direction of the second set of lines. Misalignment betweenthe first mask layer 15 and the second mask layer 20 that forms a sliveropening in the substrate (as described with reference to FIGS. 1-10), ora shared opening region 24 between the first and second mask layers 15,20 (as described with reference to FIGS. 1 and 11-14) may be filled witha fill material, i.e., selective etch material. The fill material canensure that the first set of lines and the second set of lines are notshorted together.

While the claimed methods and structures has been particularly shown anddescribed with respect to preferred embodiments thereof, it will beunderstood by those skilled in the art that the foregoing and otherchanges in form and details may be made therein without departing fromthe spirit and scope of the presently claimed methods and structures.

What is claimed is:
 1. A method comprising: first etching a substrateaccording to a first mask, wherein said first mask comprises a firstmask layer comprising first mask openings that correspond to linetrenches and a second mask layer comprising second mask openings thatcorrespond to at least one via opening, wherein a shared opening regionis present between said first mask openings and said second maskopenings, and said shared opening region exposes a sliver portion ofsaid substrate, wherein the first etching forms a first etch feature toa first depth, wherein the first etch feature comprises said at leastone via opening and the first etching forms a sliver opening in thesubstrate that corresponds to said shared opening region; filling saidsliver opening with a fill material; forming a second mask by removing aportion of the first mask; second etching said substrate exposed by saidsecond mask, wherein the second etching is selective to the fillmaterial, the second etching extends the first etch feature to a seconddepth that is greater than the first depth, and the second etch forms asecond etch feature comprising said line trenches; and filling the firstetch feature and the second etch feature with a conductive metal,wherein filling said first etch feature and said second etch featurewith said conductive metal forms lines and at least one via in saidsubstrate.
 2. The method of claim 1, wherein at least one of the linetrenches intersects with at least one of the at least one via openings.3. The method of claim 1, wherein the removing the portion of the firstmask comprises removing the second mask layer.
 4. The method of claim 1,wherein the sliver opening has a width of less than 25 nm.
 5. The methodof claim 1, wherein the fill material comprises an oxide, nitride,oxynitride, carbon containing dielectric or a combination thereof. 6.The method of claim 5, wherein the filling of the sliver openings withthe fill material comprises depositing a dielectric layer using aconformal deposition process, wherein a first portion of the dielectriclayer that is deposited in the at least one via opening has a firstthickness, and a second portion of the dielectric layer that is presentin the sliver opening has a second thickness that fills the sliveropening.
 7. The method of claim 6, wherein the filling of the sliveropenings in the substrate with the fill material comprises isotropicallyetching the dielectric layer to remove the first portion of thedielectric layer, wherein the second portion of the dielectric layerremains in the sliver opening.
 8. The method of claim 1, whereinfollowing the second etch of the substrate and before the filling of theline trenches and the via openings with the conductive metal thematerial for selective etching that fills the sliver opening is removed.9. The method of claim 6, wherein after the dielectric layer isdeposited, the second etch is conducted, wherein the second etch removesthe first portion of the dielectric layer.
 10. The method of claim 1,wherein the first etch feature further comprises a first trench in thesubstrate in a first direction, and the second etch feature furthercomprises a second trench in the substrate in a second direction, andfilling the first etch feature and the second etch feature comprisesfilling the first trench and the second trench with a conductive metalto provide a first wire and a second wire.
 11. The method of claim 10,wherein the first direction is substantially perpendicular to the seconddirection.